Costimulatory receptor mechanisms

In addition to receiving antigen-driven signals through their T cell receptors (TCRs), CD4+ T cells also require activation of the costimulatory receptor CD28 to ensure full activation. Rodríguez-Jorge et al. combined mathematical modeling of signaling by the TCR and by the pattern recognition receptor Toll-like receptor (TLR5) to predict how the two pathways could combine to induce T cell activation. Experiments then showed how the TCR and TLR5 pathways converged on the activation of critical transcriptional regulators needed for T cell activation, suggesting that TLR5 plays a role similar to that of CD28 in T cell activation.